Grantee Research Project Results
1999 Progress Report: Characterization of Factors Determining Personal Exposure to Volatile Air Toxics in Urban Environments
EPA Grant Number: R826786Title: Characterization of Factors Determining Personal Exposure to Volatile Air Toxics in Urban Environments
Investigators: Esmen, Nurtan A. , Marcham, C. , Wang, D. , Lynch, Robert A. , Hall, Thomas A. , Johnson, D. L. , Phillips, M. L. , Clinkenbeard, R.
Current Investigators: Esmen, Nurtan A. , Wang, D. , Lynch, Robert A. , Hall, Thomas A. , Johnson, D. L. , Phillips, M. L.
Institution: University of Oklahoma Health Sciences Center
EPA Project Officer: Chung, Serena
Project Period: October 1, 1998 through September 30, 2001 (Extended to September 30, 2002)
Project Period Covered by this Report: October 1, 1998 through September 30, 1999
Project Amount: $559,352
RFA: Urban Air Toxics (1998) RFA Text | Recipients Lists
Research Category: Air Quality and Air Toxics , Air
Objective:
The objective of this research project is to investigate how external factors influence the relationship between personal exposures and area measurements of air toxics and air particulate matter. Using a multicity, multiseason factorial design, we are studying the distribution of personal exposures in relation to eight dichotomous macroenvironmental and household factors that are hypothesized to influence personal activity and exposure patterns. These are: (1) the size; (2) the industrialization level of the urban area; (3) the high/low and the extreme/mild seasonal temperature; (4) the presence/absence of precipitation; (5) workday/off-day; (6) the presence/absence of children in the household; and (7) the blue collar/white collar socioeconomic status.
Progress Summary:
Year 1 of the project was devoted to the full development and/or adaptation of the research methods, the design and execution of pilot studies to validate the efficiency of the methodologies to be used, and the collection and analysis of background information. In the initial stages of the investigation, it became apparent that there was not sufficient information on the concentration levels of air toxics to complete the analysis. In contrast, there were good and reliable data sets for particulate matter in the form of both PM10 and PM2.5 measurements and source specific gases such as carbon monoxide. It was theorized that the information on particulate matter and the source specific gases could be used to estimate the crude levels of air toxics expected for the modeling of human exposures.
Preliminary analysis of concurrent airborne particulate matter determination (PM10 and PM2.5 and hourly measurements of PM2.5 in Tulsa and Oklahoma City provided some unexpected results. In both cities, approximately 75 percent (by mass) of PM10 is accounted for by PM2.5. This ratio statistically was significantly different for the two cities, but the difference was sufficiently small to be considered as practically equal. Complete time-series analysis suggested that approximately 62 percent (by mass) of the PM2.5 in Oklahoma City could be attributed to automotive exhaust. This difference was found to be statistically highly significant. In effect, this observation can be used as a corroborative evidence of the expected difference between the industrial and commercial locations that was hypothesized in the original research idea. The matched data analyses between CO concentration measurements and PM2.5 show a distinct variance reduction with 2-hour desynchronized time series, suggesting a strong photochemical particle generation component for the PM2.5.
As a pilot study for the tracking of the subjects, location tracking data have been collected in the Oklahoma City area and on trips to Tulsa, Ponca City, and McAlester. Because global positioning system (GPS) technology relies on line-of-sight reception of at least four satellites to calculate coordinates, position logging was not possible inside steel reinforced structures. When the device is turned on or moved outdoors, it typically takes 1-5 minutes for the receiver to pick up enough satellites to start logging. In the best test runs, the device was able to log nearly continuous position data throughout all outdoor activities, including driving a car. However, partial blocking of the sky by urban canyons, metal auto body panels, and other conductive materials—including the subject's own body—was found in many cases to reduce a fraction of outdoor time for which position data successfully was logged. Use of a small external antenna also was studied. This yielded somewhat improved reception with logging occurring inside some residential houses. The results of the pilot study showed the strengths and limitations of the GPS technology as a non-intrusive means of tracking individuals’ location to validate and supplement diary data.
In response to the preliminary efforts, 75 individuals had made contact with study recruiters to indicate an interest in participating in the study. Approximately 50 percent of these potential volunteers did not meet participation criteria because of age, residence outside the city limits, residence type, or the presence of a smoker in the household. Among the qualified respondents, 7 (19 percent) have returned signed consent forms, 11 (30 percent) have formally declined to sign the consent forms, and the remaining 18 (50 percent) have not yet responded to the follow-up recruitment.
Future Activities:
Currently, recruitment efforts are being augmented by increased personal contacts with environmental, civic, professional, and business groups in the four cities. The recent installation of a toll-free phone number is expected to facilitate contact from potential volunteers in Ponca City, Tulsa, and McAlester. Concurrent with this effort with the available recruits, the investigators are initiating the major sampling phase of the study. As the recruitment of the subjects progresses, we plan to complete approximately 75 percent of the sampling tasks outlined in the proposal during Year 2 of the project. Year 3 of the project will be devoted to the completion of sampling and the full analysis of the collected data.
Journal Articles:
No journal articles submitted with this report: View all 27 publications for this projectSupplemental Keywords:
monitoring, South Central, particulates., Health, RFA, Air, Scientific Discipline, PHYSICAL ASPECTS, Geographic Area, ENVIRONMENTAL MANAGEMENT, Toxics, Health Risk Assessment, Physical Processes, Risk Assessments, State, particulate matter, Air Quality, HAPS, Environmental Chemistry, 33/50, Children's Health, indoor air, VOCs, Atmospheric Sciences, Biochemistry, air toxics, Ecology and Ecosystems, Risk Assessment, Benzene (including benzene from gasoline), health effects, indoor air quality, urban air pollution, fine particulates, Oklahoma (OK), benzene, Hexane, human exposure, Toluene, activity patterns, children, exposure, hazardous air pollutants (HAPs), personal exposure, PM, urban air toxics, air pollutants, air quality models, ambient air, 2, 2, 4-Trimethylpentane, air pollution, ambient air quality, Ethyl benzene, fine particle levels, human health risk, modeling, Volatile Organic Compounds (VOCs), Xylenes, exposure assessment, Styrene, Xylenes (isomers and mixture)Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.